Accelerator and system of control.



A. J. HALL & L. G. RILEY.

ACCELERATOR AND SYSTEM OF CONTROL.

APPUCATION FILED SEPT. 27. 1916.

Patented June 12, 1917.

3 SHEETSSHEET I.

R 0 MM W E VH m n 6 ,m Y ME AN Y WITNESSES:

ATTORNEY A. J. HALL & L. G. RILEY.

ACCfiLERATOR AND SYSTEM OF CONTROL.

. APPLICATION FILED SEPT-27.1916. w 1,229,446.. Patented June 12, 1917. I a SHEETS-SHEET 2.

WlTNESSESZ INVENTORS Mrf/u/r [Ha/l ATTORNEY A. J. HALL & L. G. RILEY.

ACCELERATOR AND SYSTEM OF CONTROL. APPLICATION FILED SEPT-27p 1916- 1,229,4:46. Patented J 11116 12, 1917.

3 SHEETS-SHEET 3- UNITED STATES PATENT OFFICE.

ARTHUR T. HALL AND LYNN G. RILEY, OF WILKINSIBURG,PENNSYLVANIA, ASSIGNORS TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

Specification of Letters Patent.

ACCELERATOR AND SYSTEM OF CONTROL.

Patented June 12, 1917.

Original application filed October 5, 1912, Serial 110724965. Divided and this application filed September 1 27,1916. Serial No. 122,378.

To all whom it may concern:

Be it known that We, ARTHUR J. HALL, a subject of the King of Great Britain, and a resident of Winkinsburg, in the county of Allegheny and State of Pennsylvania, and LYNN G. RILEY, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful the control drum in either direction with an inappreciable amount of lost motion and a relatively small deterioration of the moving parts.

More specifically, it is an object of our invention to effect a step-by-step movement of the control drum by succrssively balancing and unbalancing fluid pressures upon the opposite sides of a movable piston which constitutes'a part of a fluid-actuated operating device that is mechanically associated with the control drum.

A further object of our invention is to provide a system of electric motor control that shall embody independently operated switches for governingthe main circuit connections and establishing series and parallelmotor arrangements, and adrum controller for adjusting the accelerating resistor and governing the motor acceleration.

Another objectof our-invention is to provide a system, having the above-named characteristics,vthatvshall embody means for effecting not only well known series-multiple control connections for a plurality of electric motors, but also for establishing field control connections for obtaining an addi:

- tional motor speed notch when themotors are connected in series as well as when they are connected in multiple circuit relation.

A further object'of ourinvention is to provide a control system in which a single controller drum is employedfor adjusting the accelerating resistor during both series and parallel operation, and, said drum is adapted to be operated in one direction throughout its entire travel during series operation; is then reset to a predetermined position during the transition in motor circuit connections; and is then again advanced throughout its travel to govern the acceleration during the multiple operation of the motors.

A still further object of our invention is to provide an electrically controlled fluid-actuated operating mechanism for moving a controller drum in opposite directions either in a step-by-step movement or continuously, in accordance with th'epperationof a manually .operated master controller.

Control systems for railway motors have hitherto usually comprised either a manually operated controller of the drum type adapted to directly arrange the motors for series and parallel operation and to govern the adjustment of the accelerating resistor, or a manually operated master controller and a plurality of independently operated switches for governing the motor circuits and the acceleration of the motor. Fluid operated actuating devices for control drums, of the types heretofore employed, have either failed to produce a positive step-by-step movement of the control drum and to insure that the drum was always brought to rest exactly at one of its normal control positions, or they have comprised a series of ratchets and pawls or brakes which rendered the mechanism expensive to construct and maintain, unreliable in operation, and objectionable for commercial service.

According to our present invention, we provide an extremely simple and compact -fluid actuated actuating mechanism which is electrically controlled to effect successive balancing and unbalancing of fluid presconsists of a system of electric motor control in which the fluid operated actuator above referred to, is employed for driving a motoraccelerating control drum and in Which a plurality of independently operated switches are employed for governing the main motor circuits of the system for connecting the motors in series and in parallel relations.

The independently operated switches may be of any suitable structure and operated in any suitable manner, but we prefer to employ a series. of pneumatically operated switches which are electrically governed in a well known manner and each of which is provided with a magnetic blowout and is otherwise comparable to a main circuit interrupter.

By employing our fluid actuated control drum for governing the motor acceleration, the circuit connections of the system are materially simplified, the number of train lines necessary for multiple unit control is reduced and'the apparatus embodied in'the system occupies materially less space than any: of the systems hitherto proposed 'for the same service.

In our system, the control of the motors is directly responsive to the motorman or attendant, while at the same time, the arrangement of parts is such that, if the master controller is thrown quickly from the off position to the full multiple position, the

accelerator will only operate to connect the motors in series circuit relation, so that the acceleration will not be abrupt and the motors will not be injured.

During the operation of the system, if the 7 line voltage fails, the accelerator will im- Figure 1 ofthe accompanying drawings is a sectional elevation of a drum-actuating mechanism constructed in accordance with our invention. Figs. 2 and 3 arediagrammatic views of systems of electric motor control embodying and arranged in accordance with our intention, the system of Fig. I

3 differing from that of Fig. 2 in that it embodies-four motors instead of two and is arranged for field control in addition to the usual armature control with both the series and multiple arrangement of motor conn'ec tions.

Referring to the drawings, each of the systems of control here shown con'ipriscs electric motors 1 and 2, an accelerating con trol drum 3, an actuating mechanism therefor, a plurality of independently operated control switches, a reversing switch 5 and a master switch 6. I

The actuating mechanism 4 comprises a cylinder 7, pistons8 and 9 operating therein, a connecting-lever 1O pivotally supported at 11 on the cylinder 7 and having a head or enlargement 12 interposed between the pistons 8 and 9, and magnet-actuated valves 13 and 14.

The valve 13 is normally held closed and the valve 14 is normally held open either by springs 15 and 16, as shown in Fig. 1, or by the action of gravity, as shown in the'diagrams of Figs. 2 and 3.

The respective ends of the cylinder 7 are connected by suitable pipes 17 to a tank or reservoir 18 containing compressed air or any suitable fluid medium, such for example as water, oil, air, or gas at any degree of pressure either above or below that of the atmosphere. We prefer to employ compressed air as the operating medium and in 'describiing our invention, shall therefore set it forth as so operated, although the invention should not be so limited.

The valve 13, when open, admits operating fluid from the tank or reservoir 18 to one end chamber 19 of the cylinder 7, and the valve 14, when open, admits operating fluid to the opposite end 20 of the cylinder. As above described, the relation of the valves is such that, when actuated by their respective springs or by gravity, they admit operating fluid to the end chamber 20 and exhaust it from the chamber 1 and thus force the pistons 8 and 9 and the lever 10 1 into the positions illustrated in the drawings.

\Vhen the magnet coils 21 and 22, with which the valves 13 and 14 are respectively provided, are energized. the valve 13 is opened and the valve 14 closed. Under these conditions, operating fluid is admitted to the chamber 19 of the cylinder and is exhausted from chamber 20 through exhaust port 23, and the parts within the cylinder are moved toward the chamber 20.

In order to stop the motion of the pistons at any point, it is only necessary to interrupt the supply of energy to the coil 21, thereby permitting the valve 13 to close and to connect the chamber 19 to an exhaust port 23. The operating fluid is thus quickly exhausted and the pressure equalized on op posite sidesof the pistons which act as a unit and are therefore instantly brought to rest. This successive balancing and imbalancing of pressures on the respective sides of thepistons, whereby the pistons and operatively associated mechanism are actuated in one direction or the other or if a reversing control switch 24 is moved to position 00 and the master switch 6 is moved into position a, circuit is established from a positive line conductor 25, through a trolley 26, a conductor 27, a control cutout switch 28, a conductor 29, contact fingers 30 which are bridged by a contact member 31 of the master switch, a conductor 32, contact members 33, which are bridged by a contact member 34 of a reversing control switch 24, a conductor 35, contact fingers 36, which are bridged by a contact member 37 of the reversing switch 5, a conductor 38, a coil 39 of a magnet valve 40, a conductor 41, resistor sections 42 to 46, inclusive, a conductor 47, Which ishereinafter referred to as negative conductor 47,

contact fingers 48, which are bridged by a contact member 49 of the master switch 6, a conductor 50, the control cut-out switch 28, a conductor 51 and a trolley 52 to an opposite line conductor 53. 5

Another. circuit is. established from the conductor 32 through a resistor section 54,

and the resistor sections 42-to 46, to the negative conductor 47.

Thus, the resistor sections are energized and the magnet valve 40 is opened and admits fluid pressure from any suitable source (not shown) throu a pipe 55 to a cylinder 56. A piston 5%, which operates in the cylinder, is. so actuated as to move the reversing switch 5 into position 70, in opposition to a spring 58 which tends to hold it in its position Z. A circuit is now established from the conductor 35, through contact fingers 36 and 59, which are bridged by a contact member 37 of the reversing switch 5, a conductor 60, a coil 61 of a line switch 62, a conductor 63, a coil 64 of a line switch 65, a circuit breaker 66 and a conductor 67, to a point of connection between the resistor sections 42 and 43; circuit being completed from this point as before;

A coil 68 of a switch 69 is connected in multiple circuit relation to the resistor section 43, one of its terminals being connected directly by a conductor 70, to the junction of the resistor sections 42 and 43 and the 7 other terminal being connected, through contact member 71 of a switch 72, a conductor 73, contact member 74 of a switch 75 and a conductor 76, to the junction of v resistor sections 43 and 44.

When the aforesaid 'actuatingcoils are thus energized, the switches 62, 65 and 69 are closed.

The main circuit is now completed from the trolley 26, through a switch 77, an overload release coil 78 of the circuit breaker 66, a contact member 79 of the'switch 65, accelerating resistor sections 80, 81 and 82, a conductor 83, a contact member 84 of a switch 85, a conductor 86, the armature 87 of the motor l, a conductor 88, contact fingers 89, which are bridged by a contact member 90 of the reversing switch 5, a conductor 91, contact fingers 92', which are bridged by a contact member 93 of the accelerator 3, a conductor 94, the field magnet winding 95 of the motor 1, a conductor 96, contact fingers 97, which are bridged by a contact member 98 of the reversing switch,

a conductor 99, a contact member 100 of the switch 85, a conductor 101,,the switch 69,

a conductor 102, a contact nfember 103 of a switch 104, a conductor 105, the armature 106 of the motor 2, a conductor 107, thence through reversing switch contact members in the usual manner, a conductor 108, -contact fingers 109, which are bridged by a contact member 110 of the accelerator 3, a con-.

ductor 111, the field magnet winding 112 of the motor 2, a conductor 113, thence through reversing switch contact members, in the usual manner, a conductor 114, a contact 115 of the switch 104, a conductor 116, the switch 62, the switch 77 and thetrolley 52 to the negative line conductor 53.

The motors 1 and 2 are thus connected in.

If it .is assumed that the master switch 6" tuating coil 21 for the valve 13 and the actuating coil 22 for the valve 14, parallel conductors 118 and 119,.contact fingers 120 and 121, contact members 122 and 123 of. the accelerator 3, and contact fingers 124 and 125 which are joined by conductor 126 to a finger 127 of the master switch, from which point a single circuit continues through a contact member 128 with which the finger 127 is now in engagement, and a contact finger 129 to conductor 47, from which point a circuit is completed to the negative line conductor, as before.

The coils 21 and '22, when energized, serve, respectively, to openthe valve 13 and close the valve 14. Operating fluid is, consequently, admitted from the tank or reservoir 18'i 'through the pipe 17 and the valve 13 to cylinder chamber 19 and, by reason of the unbalancing of fluid pressures,

the pistons 8 and 9 are so moved as to adjust the accelerator 3 from a position m to a position a. The progress of the pistons 8 and 9' is stopped at this point by reason of the fact that the contact finger 124 is disengaged from contact member 122 and therefore the coil 21 is deenergized and the valve 13 is closed to reestablish balanced atmospheric pressures.

When the accelerator occupies position n,

contact fingers 130 engage a contact member 131 of the accelerator 3 and short-circuit the resistor sect-ion 80, The motors 1 and 2 are consequently accelerated and as the master switch 6 occupies successively positions 0, d and 'e, the coil 21 of the valve 13' is successively made and broken by reason of the successive engagement of contact fingers 132, 133 and 134, with the contact member 128 of the master switch and the successive disengagement of the fingers 135, 136 and 137 from the contact member 122 of the accelerator 3. Consequently, the pressures on the respective sides of the pistons are successively unbalanced and balanced whereby,the accelerator is moved to occupy successively positions 0 and p and g. In position 0, the finger 138 moves into engagement with a section of the contact member 131, and in position p a contact finger 139 is brought in engagement with the same section, thereby successively shortcircuiting the resistor sections 81 and 82.

The motors are thus connected' in series relation directly across the circuit, with the resistor sections 80, 81 and 82 excluded.

-When the accelerator occupies position 9, a

95 and 112 is short-circuited and, conse-- quently, the speed of the motor is increased. If desired, the master controller 6 may be moved initially to position a or to any intermediate position, thereby causing the accelerator to move up to a corresponding position.

In systems of unit switch control, it has hitherto been impracticable to provide a field control step when the motors were connected in series relation, on account of the com 'ilexity of the system,'but, as above indicated, it is possible to secure field control 1n the system of our invention without difficulty.

If the master switch is moved from position 0 to position 7, contact fingers 132, 133 and 134 are disengaged from the contact into engagement with the contact member pressure conditions, the istons Sand 9 are returned toward the position in which they are shown inFig. 2.

' As soon as the accelerator returns to positionn, the finger 125 engages the contact member 123'and a pair of contact fingers 143 and 144 are bridged by the interconnected contact members 145. The circuit of the relay switch coil 22 is thus reestablished, closing the valve 14 and bringing the pistons 8 and 9 to rest by reason of the resulting equalized pressure in the end chambers 19 and 20. Thus, only sections 81 and 82 are included in circuit during parallel operation. Obviously, the contact members 123 may be designed to effect engagement with contact member 125 in any operating position, in order to arrest the backward or resetting movement andto provide for the inclusion of any number of resistance sections during the parallel operation of the motors.

The bridging action just referred to causes a circuit to be established from the conductor 117, through contact fingers 143 and 144, which are bridged by the members 145, a conductor 146, contact fingers 147 which are bridged by a contact member 148 of the switch 69. a conductor 149, a coil 150 of the switch 72, a conductor 151 and the contact finger 142, to the contact member 128, from which point circuit is completed as above indicated.

The switch 72 is thus closed and the circuit. which was previously completed througlrthe coil 68 of the switch 69 and the contact member 71 of the switch 72, is interrupted. The switch 69, which is hereinafter referred to, for convenience, as the series switch of the system, is thus permitted to open and, in opening, completes a circuit from the junction of the resistor sections 44 and 45 through a conductor 152, a coil 1.53 of the switch 75, hereinafter referred to as the parallel switch of the system, a conductor 154, contact fingers 155 and 147, the conductor 149, the coil 150, the conductor 151, etc, as before. The new circuit thus includes not only the coil 153 of the parallel rc-inserts the short-circuited section of the field magnet windings 95 and 112. The closing of the parallel switch 75 and the switch 72 and the opening of the series switch 69 moved step-by-step into its positions 0, p-

and q, thereby successively short-circuiting the resistor sections 81 and 82 and a section of the field magnet windings.

By reason of the location and function of the fingers 143 and 144 and the contact member 145, the motorman or operator must rest his master switch at full series position 6 in order to cause the motors to accelerate through their various positions, until finally the full multiple position is reached. This is evident from the fact that if the master switch is thrown rapidly to the position 2',

there is nothing tocause. the accelerator to return to the position n after it reaches the position 9 the first time, and, consequently,

the motors will remain connected in full series with weakened fields and it will be impossible to obtain further acceleration without first returning the master switch to position a.

From the foregoing description, it is evident that either a successive notch-by-notch movement, corresponding to the movement of the master controller, may be effected throughout both series and parallel operation, or the accelerator may be moved continuously up to full series position with weakened field, after which the transition is accomplished and the continuous movement thereof. maybe resumed up to full parallel position with a partially short-circuited field.

A field control notch is provided both for series'and for parallel operation, and, moreover, the same accelerating apparatus is utilized for eliminating the same resistor sections during bothTgeriods ofoperation, the apparatus being reset or moved back to substantially its initial'position just prior to the series parallel transition.

Provision is also made for accomplishing a step-by-step or a continuous backward movement of the accelerator from any position, whereby the Operator may drop back to any notch for a slower speed of operation without being obliged to first return the controller, to the ofi position and then to notchup to the desired position.

Assume, for instance, that the master controller occupies its full parallel position e and it is desired to run at a lower speed, corresponding to the first parallel position, the master controller is moved to position 7", thereby disengaging contact terminals 132,

133 and 134 and their respective corresponding terminals on the accelerator which cooperate withthe segments 122 and 123, and concurrently energizing contact terminal 127 and corresponding terminals 124 and 125 on the accelerator.

Thus, coils 21 and 22 of the valves 13 and 14 are simultaneously deenergized and remain so, until the accelerator has moved back to position n, which action'is effected by reason of the unbalanced pressures on the pistons caused by the opening of the valve 14 and the closure of valve 13.

When position n is reached, terminal 125 engages segment 123 and energizes coil 22: to close valve 14 and establish balanced pressures on the piston which brings the accelerator to rest.

In Fig. 3 of the drawings, the corresponding parts are. referred to by the same reference characters, the system being similar to that of Fig. 2 except that four motors are utilized instead of two, and the arrangement of circuits and train lines is such as to adapt the system for operation on a ground return circuit, while the system of Fig. 2, as indicated by the two trolleys 26 and 52, is adapted for what is known as a metallic return system in which both of the conductors are tem of Figs. 2 and 3, and, consequently, we

desire that only such limitations shall be imposed as are indicated in the appended claims.

We claim as our invention:

1. In a control system, the combination with a plurality of electric motors, a plurality of independently actuated motor-circuit switches for arranging said motors for series and parallel operation, an accelerating resistor, a control drum for govern ng the resistor, and a master switch, of a fluid actuator for the accelerating drum comprlsing a cylinder, :1 piston operatively connected to the drum, and means dependent upon the master switch for governing the fiuld pressure in the cylinder.

2. In a control system, the combination with an electric motor, a plurality of control switches, an accelerating resistor, a control drum for governing the resistor, and a" master switch, of a fiu'id actuator for the control drum comprising a piston operatively associated therewith, a cylinder in which the piston operates, and magnetactuated valves for controlling the supply or? fluid to the cylinder, the operation of both of said valves being dependent upon the master switch and upon the control drum.

3. ln a control system, the combination with an electric motor, a plurality of control switches, an accelerating resistor, a control drum for governing the resistor, and a master switch, of a fluid actuator for the control drum comprising a piston operatively connected thereto, a cylinder in which the piston operates, and magnet actuated valves for controlling the supply of fluid to the cylinder, said valves being operatively dependent upon the master switch and upon the control drum and being adapted, when their actuating magnets are de'energized, to admit fluid at one end of the cylinder only, whereby the control drum is biased to one extreme position.

' 4. In a control system, the combination with an electric motor, a plurality of control switches and a master controller, of an accelerating controller having a plurality of main circuit stationary and movable contact members, and a fluid-actuator for the movable members comprising a piston operatively connected thereto, a cylinder in which the piston operates, a pair of valves for governing the supply of fluid to opposite ends of the cylinder, one of said valves being normally closed and the other normally open, and means dependent upon the positions of the master controller and the accelerating controller for governing the valves. 5. In a control system, the combination with an electric motor, a plurality of control switches and a master controller, of an accelerating controller having a plurality of main circuit stationary and movable contact members, and a fluid-actuator for the movable members comprising a piston operatively connected thereto, a cylinder in which the piston operates, a pair of valves for governing the supply of fluid to opposite ends of the cylinder, one of said valves being normally closed and the other normally open, and means dependent upon the positions of the m: ster controller and the accelerating controller for governing the valves to produce a step-by-step movement of the accelerating controller.

(3. The combination with an electric motor, an accelerating resistor, and a control drum for governing said resistor, of means for temporarily returning said drum to substantially its initial position during the acceleration of the motor.

7. The combination with a plurality of motors, means for arranging the motor circuits for series and parallel operation, and an accelerating resistor, of a control drum for governing said resistor, and means for temporarily moving said drum backward during the transition from series to parallel connections.

8. The combination with a plurality of motors, a plurality of independently actu-' ated switches for arranging the motor clrcuits for series and parallel operation, and an accelerating resistor, of a control drum for governing said resistor, said drum being adapted to be moved throughout substantially its entire travel during both the series and the parallel operation.

9. The combination with a plurality of motors, a plurality of independently actuated switches for arranging the motor circuits for series and parallel operation, and an accelerating resistor, of a control drum adapted to eliminate substantially the whole of said resistor both during series and parallel operation and electro-responsive means for resettin said drum to substantially its initial positlon during the transition from series to parallel.

10. The combination with a plurality of motors, means for arranging the motor cir cuits for series and parallel operation, an accelerating resistor, and a switching device for controlling said resistor and for weakening the field strength of said motors during series operation, of means for returning said switching device to substantially its initial position subsequent to series operation whereby said switching device similarly controls said resistor and the motor field strengths during parallel operation.

11. The combination with a plurality of motors, means for arranging the motor circuits for series and parallel operation, an

accelerating resistor, and meansfor controlof said motors.

12. The combination with a plurality of motors, means for arranging the motor circuits for series and parallel operation, and an accelerating resistor of means for governing said resistor, electro-responsive means for efi'ecting predetermined movements of said governing means during series operation and for resetting said governing means and eflecting substantially the same movements thereof during parallel operation.

13. The combination with a plurality of electric motors, a resistance-controlling devlce, means for moving said device through predetermined steps during series operation of said motors, means for resetting said device, means to restablishing parallel connect1ons for said motors subsequent to the resetting operation, and means for causing said device to substantially duplicate its movements during parallel operation.

14. In a system of control, the combination with an electric motor, a resistor. a controller adapted to occupy a plurality of positions for effecting field control of said motor and governing said resistor. and an electrically controlled power device for actuating said controller, of a manually operated master controller, and auxiliary electrical electrically controlled power device for actuating said controller, of a master controller,

and auxiliary electrical control means adapted to occupy a plurality of positions cortesponding to the motor circuit controller or governing the operation of said power device.

16. In a system of control, the combination with an electric motor, a resistor, a controller. adapted to occupy a plurality of positions for effecting field control of said motor and governing said resistor, and an electrically controlled power device for actu ating said controller, of a master controller,

and an auxiliary control device associated resistor governing controller for governlng With said motor circuit controller and having interlocking means adapted to be connected in an energizing circuit of said electrically controlled power device for governing the operation of said power device and said controller.'

17. In a control system, the combination with an electric motor, an accelerating resistor, a controller for arranging the circuits of said motor and said resistor, and electrically governed fluid-actuated means embodying a movable piston, for effecting movements of said controller, of a master controller for manually controlling the en ergizing circuitsof said electrically governed fluid-actuated means and a coo cratingauxiliary control device associate with said motor circuit controller and having interlocking means corresponding to each position of said motor circuit controller for intermittently making and breaking an energizing circuit of said. electrically governed fluid-actuated means whereby successive balancing and unbalancing of fluid L pressures on opposite sides of said piston is effected to cause a step-by-step movement of said motor circuit controller through all of its positions.

18. In a control system, the combination with an electric motor, an accelerating resistor, a main controller-for adjusting the circuit connections of said motor and said resistor, and a fluid-actuator for said main controller comprising a cylinder, a movable piston, and electrically controlled valves. at each end of said cylinder for admitting and releasing an operating fluid'to and from said cylinder, of a manually operated master controller for governing the circuits of said electrically "controlled-valves, and an auxiliary'control device mechanically associated with said main controller for governing the operation of said electrically controlled valves. V

19. In a control system, the combination with an electric translating device, a resistor, a main controller for adjusting the circuit connections of said translating device and said resistor, and a fluid-actuated device for said controller comprising a cylinder, a movable piston, and electrically controlled valves governing the admission and release of an operating fluid to and from the respective sides of said piston, of a manually operated master controller and an auxiliary interlock controller associated with said main controller ,for' alternately energizing and deenergizing certain of said valves for effecting a step-by-step movement for said main controller.

20. In a control system, the combination with a plurality of motors, a plurality of independently operated unit switches for connecting said motors in series and in parallel relation, and a power-actuated accelerating the acceleration of the motors in both series and parallel arrangements, of a master controller and other control means for governing the operation of said unit switches and power-actuated controller, and means for preventing the transition from series to parall-e1 if the master controller is moved directly to one of its parallel positions.

21. In a system of, control, the combination with a plurality of electric motors, and

means for effecting series and parallel circuit connections for said motors and for governing the acceleration thereof, of a master controller adapted to occupy a plurality of series and a plurality of parallel operating positions, other control means cooperating with said master controller for governing the operation of said motors, and means for necessitating the operator to temporarily hold the master controller in its full series position before moving it into any of its parallel positions.

22. In a control system, the combination ity of independently actuated unit switches for connecting said motors in series and in parallel relation, an accelerating resistor-and a control drum for governing said resistor and having a plurality of operating positions, of means for actuating said control drum in a forward direction for controlling the acceleration of said motors, and means for temporarily returning said control drum to a predetermined operating position just prior to the transition of the motors from series to parallel relation.

24. The combination with a plurality of electric motors, means for arranging the motors for series and parallel operations, an accelerating resistor, and means for controlling said resistor during both series and parallel operation and for controlling the motor field strengths during at least one of said operating conditions, of means for temporarily returning said last-named means to a predetermined position prior to the transition of motor from series to parallel operation.

25. The combination with a plurality of electric motors, means for connecting said motors for series and parallel operation, a plurality of accelerating resistors connected in circuit with the motors during series operation, a resistor-governing controller drum, means for-advancing said controller drum to progressively exclude said resistors during series operation, means for resetting said controller drum to a predetermined position prior to the transition from series to parallel operation whereby a less number of resistors are connected in circuit during parallel operation, and means for initiating the operation of said advancing means to effect the exclus on of said resistors during parallel operat.,n.

26. In a control system, the combination with a plurality of electric translating de- Vices, of a plurality of independently operated unit switches for connecting said devices in series and parallel relations, a current-limiting resistor, an independent resistor-controlling drum, and a master switch for governing said unit switches and said resistor controlling drum, and means for preventing the transition from series to parallel if the master switch is moved directly to one of its parallel positions.

27. A control system comprising a drum controller for governing a'motor circuit and having a plurality of operating positions, and a pneumatic mechanism for actuating said drum controller comprising a piston, a cylinder nd valve magnets for, governing the admission and release of operating fluid to and from the opposite ends of said cylinder, of a master controller and an interlock controller associated with said drum controller and both having positions corresponding to the positions of said drum controller for governing the operation of said valve magnets.

28. In a control system, the combination with a plurality of electric motors, an accelerating resistor, a controller drum for governing said resistor, and a power-actuated device for actuating said controller drum, of a plurality of independently actuating series and parallel unit switches for effecting, in part, the transition of motors from series to parallel relation, and means for controlling said power-actuated devices and said series and parallel switches.

29. In a control system, the combination with a plurality of electric motors, an accelerating resistor, a controller drum for governing said resistor, and a power-actuated device for actuating said controller drum, of a separate and independentunit switch for effecting, in part, the transition of 1110- tors from series to parallel relation, and a master switch for controlling said poweractuated device and said unit switch.

30. The combination with a main controller, a fluid-actuated mechanism therefor comprising a piston, a cylinder, and electromagne'tically controlled valves for governing the admission of an operating fluid to the opposite sides of said piston, of an auxiliary controller operatively associated with said main controller for successively changing the circuit connections of certain of said valves in each position of said main controller, and a master switch cooperating with said auxiliary controller for governing the operation of said valves.

' 31. The combination with a controller, of fluid-operated means therefor comprising a pair of pistons operatively connected to said controller, cylinders in which pistons operate, electro-magnetic valves for controlling the admission of operating fluid to said respective cylinders, one'of said valves be ing normally open and the other being normally closed whereby the controller is biased to its off position, and control means for governing the supply of energy to said valves whereby a definite step-by-step movement of the controller is effected.

' 32. The combination with a main controller, and an actuating device therefor comprising a cylinder, a piston movable therein, and a plurality of electrically controlled valves at the respective ends of said cylinder, of an auxiliary control drum actuated by said main controller and having interlocking means corresponding to each position of said main'controller and adapted to successively vary the connections of an energizing circuit of one of said electrically controlled valves in the several positions of said main controller.

33. The combination with a controller, a fluid-actuated mechanism for said controller comprising a piston, a cylinder and Valve magnets for governing the admission and release of fluid to and from said cylinder, of an auxiliary controller operatively connected to said controller for successively deiinergizing certain of said valve magnets in each position of said controller whereby successive balancing and unbalancing of fluid pressures on opposite sides of said piston is effected, and a master switch cooperating with said auxiliary controller for governing the operation of said valve magnets.

3%. The combination with a main controller, a fluid-actuated mechanism for actuating said main controller comprising a piston and a cylinder, and valve magnets for governing the admission and release of fluid to and from the opposite ends of said cylinder, of a master controller, and means dependent upon the position of said main controller for governing the operation of said valve magnets.

35. The combination with a main controller, an operating head therefor comprising a pair of pistons operatively connected to said main controller, cylinders in which said pistons operate, and magnet valves for controlling the admission and release of fluid to and from said cylinders, one of said valves being normally closed and the other normally open when deenergized, whereby said main controller is biased to its oii' position, of an auxiliary control device dependent upon the position of said main controller, and a master controller for causing certain of said magnet valves to be intermittently energized to edect a step-by-step movement of said main controller.

36. The combination with a main controller, an. auxiliary controller operatively connected to said main controller, an operating head therefor comprising a pair of pistons operatively connected to said main controller and said auxiliary controller, cylinders in which said pistons operate, and

valve magnets for controlling the admission of fluid pressure to said cylinders, one of said valves being normally open and the other normally closed when denergized, whereby said main controller is biased to its off position, and a master controller cooperating with said auxiliary controller for governing theenergization of said magnet valves to produce a step-by-step movement of said main controller.

37. The combination with a main controller, of an operating head therefor comprising a pair of pistons operatively connected to the main controller, cylinders in which "the pistons operate, magnet valves for controlling the admission of fluid pressure to the cylinders, one of said valves being normally open and the other normally closed whereby the main controller is biased to its ofi position, and control means for governinn; the supply of energy to the magnet valves, whereby step-by-step movement of the main controller is produced.

38. The combination with a main controller, fluid-actuated means therefor comprisinga cylinder, a piston, and valves for controlling the admission of an operating fluid to the respective sides therepf, of a master controller and an auxiliary interlock device associated with said main controller for conjointly governing the operation of said valves, whereby the main controller may be actuated either continuously or in a series of definite steps in accordance with the manipulation of the master controller.

In testimony whereof, we have hereunto subscribed our names this 25th day of Sept, 1916.

ARTHUR J. HALL. LYNN G. RILEY. 

